iOS RevenueCat Error 401 on /receipts POST

Question

I'm not able to complete a POST request to RevenueCat/iOS. It works fine on development (apple Sandbox test), but it fails on Production (returning 401). I'm passing correctly the REVENUE CAT API KEY on the Authorization token. See my curl request below:

curl --request POST \
     --url https://api.revenuecat.com/v1/receipts \
     --header 'Authorization: Bearer REVENUECAT_API_KEY' \
     --header 'Content-Type: application/json' \
     --header 'X-Platform: ios' \
     --header 'accept: application/json' \
     --data '
{
     "product_id": "my_plan",
     "price": 20.00,
     "currency": "USD",
     "is_restore": "false",
     "app_user_id": "xxuu8888ss",
     "fetch_token": "MY_BASE_64_RECEIPT_STRING"
}
'